Oil wells are generally formed by drilling a bore into the earth for accessing buried crude oil deposits, and then installing a variety of equipment within the bore to enable pumping of crude oil up to the earth's surface. During drilling, hollow metallic tubes (also known as ‘casings’) are inserted within the bore to prevent walls of bore from collapsing. In a deep enough bore, multiple hollow casings are installed vertically one above the other by screwing ends of adjacent sections with each other. The entire assembly of attached casings is commonly known as ‘bore casing’.
Once a bore casing is formed, a variety of equipment (including crude oil pumping equipment and sensor equipment) is installed within the bore casing. In an operational oil well, crude oil is pumped to the surface of the earth from the buried crude oil deposits with the help of pumping equipment installed in the bore casing. However, the oil well production unit is vulnerable to failure of installed equipment within the bore casing, which can be caused by mechanical fatigue or electrical shorts or other problems, which can be exacerbated by changed conditions within the well-bore.
During installation of pumping equipment, or during troubleshooting of failed equipment in an operational oil well-bore, it is often necessary to retrieve equipment from the bore casing (also known as fishing). Retrieval of equipment which may be imperfectly installed or lie stuck within the bore casing, can be accomplished by grasping it with an overshot tool (having jaws) connected to the coiled tubing. Jaws of an overshot are generally opened and closed by rotation provided to the overshot. Additionally, rotation provided by the overshot can help to set free stuck equipment. Since the coil tubing cannot be rotated easily—but it can be moved up and down linearly from a drum powered by a drive motor, a mechanical transfer of linear motion of the coil tubing into rotational motion is required.
A rotating tool can be used in a well-bore with coil tubing in conjunction with a drilling jar. See e.g. U.S. Pat. No. 8,151,910 (incorporated by reference). While the drilling jar generates impacts and resultant shock waves along the coil tubing to aid in freeing the tubing or stuck equipment, the rotating tool generates rotation for the overshot and rotation for freeing the stuck equipment. The current designs of rotating tools do not work well with the hard accelerations needed to be applied to the coil tubing (it must be jerked up or down, or both) to generate the jarring effect. The current designs tend to rotate too freely, which can cause tools designed to operate when rotated to be unintentionally activated. The rotating tool described below solves these problems with the existing rotating tools.